Hurricane Gert has maintained category 1 hurricane strength for 24 hours as of 5 PM Tuesday. The second hurricane of the 2017 Atlantic season formed about two weeks ahead of schedule. Climatologically, the second hurricane of the Atlantic season forms on August 28th. Gert strengthens some Tuesday afternoon. As of 5pm max sustained winds top out at 80 mph and pressure is down to 981 mph. Enhanced satellite imagery shows the hurricane is elongated some from north to south due to moderate north/northwesterly shear. Visible satellite imagery showed hints of an eye Tuesday afternoon. Gert passes between the U.S. and Bermuda Wednesday as a stronger category 1 hurricane. It will transition to post tropical system over cooler north Atlantic waters by Friday.
While Gert passes safely east of the eastern U.S., surf builds northward through mid-week. The risk for rip currents increases at Mid Atlantic and Northeast U.S. beaches.
Behind Gert are three areas of interest in the Atlantic. The African wave train is in full swing and there are a few areas to watch through next week. As of Tuesday afternoon there is a medium chance Invest 91L and Invest 92L develop over the next 5 days. Another tropical wave near Africa has a low chance of developing over the next 5 days.
The odds of tropical depression development have dropped some for Invest 91L. Computer models have back off some on development as there is some dry Saharan air nearby. The graphic below is courtesy NOAA/The University of Wisconsin. The 12Z European model suggests a weak tropical storm may approach the Lesser Antilles by Friday. The model shows the system weakening further as it moves westward through the Caribbean. The latest GFS shows a weak tropical storm will also form Wednesday or Thursday before it approaches the eastern Caribbean. This run is much further south than previous runs with a path through the Caribbean too. Model consensus is pretty good that Invest 91L will headed due west into the Caribbean.
Meanwhile confidence increases some that newly pinned Invest 92L will develop into a named storm. 12Z models take this disturbance more northwesterly. Some as a possible strengthening hurricane. As of now, this path is east of the U.S.. Stay tuned. The next named storms are Harvey, Irma and Jose.
Tropical Storm Gert strengthens Monday. The storm develops good outflow and convective banding. As of the 5 PM advisory max sustained winds are just shy of hurricane strength at 70 mph as it moves north at 8 mph. Pressure has dropped steadily throughout the day and Gert will likely become the 2nd hurricane of the 2017 Atlantic Hurricane season Monday night. Gert will strengthen through mid work week over warm waters before it transitions to an extratropical low in the North Atlantic by Thursday. It is no threat to the Eastern U.S., but waves and rip currents build northward over the next few days.
Invest 91L bears watching southwest of the Cabo Verde Islands. The disturbance rolled off the coast of Africa over the weekend. The elongated area of low pressure could gradual organize in the days ahead. As of Monday afternoon there is a 60% chance a tropical depression forms over the next 5 days. Until this feature gets a chance to consolidate, computer models will continue to struggle with the long range-track. There has been a lot of run to run inconsistency, which is often the case with a developing tropical disturbance.
Wind shear near Invest 91L is low to moderate and the area of low pressure is in a moist environment as it moves west at 15 mph. Drier air in the mid levels of the atmosphere is nearby to its west and north, so development will be a gradual process. Invest 91L will likely moisten that path ahead of this dry air.
Computer models show a west and eventually west-northwest track through Saturday. This puts a possible tropical depression near the Leeward Islands early Saturday. Beyond the weekend there are even more question marks. The latest Euro is less impressed with Invest 91L down the road and brings a weak tropical storm (Harvey) through the Caribbean through early next week. The GFS also shows a weak system/eventual open wave but suggests a more northwesterly track near Turks and Caicos early next week. Stay tuned as there will likely be more big changes in the models in the days ahead.
Behind Invest 91L may be another area of interest in the Atlantic, according the ECWWF. The Atlantic Basin heats up.
Tropical Depression 8 combats some drier air aloft early Sunday. As of 11 AM max sustained winds are 35 mph and it moves NNW at 13 mph. It will strengthen to Tropical Storm Gert by Sunday afternoon or evening under favorable upper level winds as it moves northward. The future 7th named storm of the 2017 Atlantic season will strengthen some through early work week. A trough across the East coast will guide it out to sea. It is the no threat to the U.S. or Bermuda, but future Gert will enhance swells and rip currents at some East coast beaches through mid work week.
A healthy African tropical wave is pinned Invest 91L Sunday morning. This is one to watch in the long-run. Gradual development is expected over the next few days as it moves west or west-northwest into the Main Development Region at about 10-15 mph. At this pace it will approach the Eastern Caribbean on Friday. Here are early 12Z computer models showing the general westward track through the work week.
While the GFS is pretty aggressive on tropical cyclone development (Harvey) in the days ahead, the ECMWF is a little more bullish. It puts a tropical storm north of Puerto Rico by next Sunday morning. We’ll have to watch the positioning of the Bermuda high in 7-10 days for possible U.S. impacts. There is plenty of time to watch Invest 91L.
Tropical wave activity will increase in the weeks ahead as the Main Development Region moistens up. By next weekend the ECWMF suggest there are 3 areas worth watching in the Atlantic. Now is the time to update your hurricane kits and stay tropical weather aware. The climatological peak of hurricane season is less than one month away on September 10th.
Invest 99L shows signs of life early Saturday. Wind shear in the vicinity has dropped and the area of low pressure organizes some east of Turks and Caicos and the Bahamas. Convection increases over warm Atlantic waters, but there is still some dry air in its path. Invest 99L has a high chance of becoming a tropical depression over the next couple of days. If it reaches tropical storm strength it will become Gert.
A northwest/northerly track is expected through early Monday. A trough will safely guide it east of the U.S. early this work week. Swells and an increase in rip currents are possible at some East coast beaches early in the week.
Elsewhere the Atlantic is quiet overall. A new tropical wave coming off of Africa is worth watching. There is some model support for development. This is the time of year that low pressure can spin up quickly. All eyes are on the ITCZ in the coming weeks. This is where the strongest storms of the season often originate in August and September.
Some of the remnants of Franklin crossed over into the East Pacific Basin Friday and became Tropical Storm Jova. It will stay a minimal tropical storm and dissipate due to a combination of drier air and cooler waters in a few days.
Tropical Storm Franklin made landfall late Monday night on the east coast of the Yucatan Peninsula with 60 mph. As of 2 PM Tuesday max sustained winds are down to 40 mph. While it has weakened over land since then, deep moisture still fuels torrential rains. 4-8 inches of rainfall, with isolated amounts near a foot are possible through Wednesday. Franklin will recharge over the southern Gulf of Mexico Tuesday night and early Wednesday. It will get close to hurricane strength before wind shear ramps up. A second landfall is likely by early Thursday in mountainous east Mexico. Mudslides and flash flooding are possible in this region. Up to 15 inches of rain is possible through late work week. Below is the 11 AM official track from the National Hurricane Center.
As mentioned the past few days, Invest 99L struggles east of the Lesser Antilles with dry air and increased upper level winds. Tropical cyclone development is highly unlikely over the next few days as the weak area of low pressure moves west-northwest at about 15 mph.
By Friday or the weekend the disturbance moves over the warm waters east of the Bahamas. The past 3 runs of the ECMWF suggest Gert will develop and strengthen during this time, possibly as a hurricane, by late in the weekend east of the Southeast U.S.. A developing trough could keep possible future Gert just off the East coast, but it’s too early to say for sure. The CMC is also on board. Meanwhile the GFS. It’s a wait and see situation late in the week.
The 6th named storm of the 2017 Atlantic Hurricane Season, Franklin, gradually strengthens Monday. As of 11 AM max sustained winds are at 60 mph and it heads west-northwest at 14 mph. The storm develops better outflow and thrives off of warm Western Caribbean waters in the mid to upper 80s. Upper level winds favor further intensification before landfall late Monday night and early Tuesday in the Yucatan peninsula. While the 11 AM National Hurricane Center forecast keeps Franklin below hurricane strength, it could become the first hurricane of the season. Hurricane Reconnaissance Aircraft will investigate Monday afternoon and get a better grasp on the strength of the storm. The graphic below shows the incredible GOES 16 enhanced satellite. This data is preliminary/non-operational.
Franklin will emerge in the Bay of Campeche Tuesday night and likely strengthen (possibly rapidly) to near hurricane strength before landfall in mountainous East Mexico early Thursday. It is no threat to the U.S..
Franklin brings tropical storm conditions and the threat for flash flooding to Belize and the Yucatan through early work week. 3 to 6 inches, with isolated amounts of 12 inches, are possible through Wednesday. That heavy rain threat shifts to East Mexico mid to late work week.
It doesn’t look promising for Invest 99L the next 5 days as it moves west-northwest at 15 mph. Upper level winds are on the rise and stay unfavorable for tropical cyclone development over the next few days. Dry African air will also hinder development.
By late in the week conditions are a bit more ripe for tropical depression development near the warm waters near the Bahamas. We will keep an eye on it.
There are two areas of interest Sunday in the Atlantic. Invest 90L south of Jamaica has organized some the past 24 hours. While convection blossoms early Sunday, moderate northwesterly shear displaces it on the eastern side of the tropical wave. Sunday’s Hurricane Reconnaissance mission was rescheduled for Monday afternoon. During this time upper levels will favor further organization, and there is a high chance Invest 90L becomes a tropical depression/Tropical Storm Franklin over the next 5 days. It is moving west-northwest towards Belize and the Yucatan Peninsula Monday.
Beyond Monday/early Tuesday models are in line with a track into the Bay of Campeche. This area is known for its very warm waters. Tropical cyclones often strengthen rapidly here. Many models are on board with a Hurricane Franklin (GFS/ECMWF/HWRF) by Wednesday or Thursday moving onshore in mountainous East Mexico. Models have trended a bit further north, so interest in extreme southern Texas should keep a watchful eye.
Invest 99L has not organized in the Atlantic. Some dry air in the mid levels of the atmosphere keeps convection disorganized early Sunday. The area of low pressure is elongated due to some marginally favorable upper level winds. Wind shear increases as Invest 99L moves west-northwest at 15 mph towards the Lesser Antilles. There is a medium chance it becomes a tropical depression over the next 5 days.
12Z computer models have really backed off on the intensity of Invest 99L. A few days ago some were anticipating a hurricane in the long run. More models are trending towards a west-northwest path north of the eastern Caribbean.
Even if Invest 99L does not become a tropical depression/named storm over the next 5 days it will still be monitored late in the week. Water temperatures are plenty warm for tropical cyclone intensification in the Eastern Caribbean and near the Bahamas.
The Atlantic Basin is active Saturday. Invest 90L in the Caribbean and Invest 99L in the Atlantic are worth keeping an eye on in the days ahead. Invest 90L is a little more organized early Saturday. Scattered convection trying to consolidate under lighter upper level winds circled in orange. It has a medium chance of development the next 5 days, especially if it survives the track across Central America/the Yucatan and enters the Bay of Campeche Tuesday or Wednesday. This is a hot spot for tropical cyclone development this time of year. Meanwhile Invest 99L southwest of Cabo Verde Islands still battles some dry African air and is disorganized. The likelihood is still high a depression forms over the next 5 days. It moves northwest at 15 mph and approaches the Lesser Antilles mid work-week. The next named storms are Franklin and Gert.
As is always the case with a disorganized, developing tropical disturbance there are some model discrepancies with the forecast track and intensity. The Bermuda High guides Invest 99L on a general west-northwest track towards the Caribbean over the couple of days. The European model is not impressed at all with Invest 99L and does not develop a tropical depression. The GFS is trending weaker too, but shows some development in the days ahead. A weaker system would tend to head more westerly towards the Caribbean while a stronger system would head more northerly. It is way too early to speculate possible U.S. impacts, if at all.
If Invest 99L survives the track into the Eastern Caribbean/interaction with some of the islands we need to keep an eye on it. Water temperatures are in the mid to upper 80s. Some areas are running 0.5°C-2°C above average, especially in the western Caribbean. Also of note is an incredibly warm Bay of Campeche where Invest 90L may head.
Upper level winds favor further organization of Invest 90L as it moves west-northwest at 10-15 mph. If some of the energy holds together and spills in the southern Gulf of Mexico mid to late work week it could rapidly intensify.
The ECMWF wind shear model shows favorable upper level winds over a very warm Bay of Campeche next Thursday morning. The Euro still suggests a strengthening named storm late work week. The 0Z brings a strong tropical storm into mountainous East Mexico Thursday. (either Franklin or Gert). The GFS also spins up a low, albeit weaker, in the southern Gulf Wednesday. It also suggests a track into East Mexico.
Emily barely hangs on as a Tropical Depression Tuesday over the warm western Atlantic. The sheared disturbance combats drier air aloft and will stay disorganized as it heads northeast and out to sea. Wind shear near a stalled frontal boundary will take a toll on Emily and it will lose tropical characteristics mid week, if not sooner. It is no threat to land in the days ahead.
As we saw with Emily, any areas of convection sitting over Gulf of Mexico temperatures in the mid to upper 80s are always worth keeping an eye on. An area of disturbed weather has flared up early Tuesday over the central Gulf of Mexico. While there are no signs of tropical development, we will monitor this feature. An old frontal boundary across the north central Gulf could guide these showers and storms toward Florida in the days ahead.
Tuesday is the start of the third month of the Atlantic hurricane season. On average, the first hurricane in the Atlantic forms on August 10th. It is a month where tropical wave activity ramps up off the coast of Africa and moistens the Main Development Region between the Caribbean and Africa. The Gulf of Mexico, Caribbean, western Atlantic and central and eastern Atlantic are all fair game for tropical cyclone development. While on average only 8% of named storms form during July, 27% of named storms form in August.
We’re watching a few disorganized tropical waves in the south central Atlantic Tuesday. They are all situated just south of the most extensive dry Saharan air and are headed westward. Some gradual development of the tropical wave circled in white is possible over the next day or two.
Long-range computer models have been back and forth the past 2 days . A tropical wave in the next week/week and a half could strengthen as it approach the Caribbean. Below is the 0Z Euro for next Thursday. It shows a healthy tropical wave southwest of the Cabo Verde Islands. The latest GFS shows a disturbance enters the Caribbean mid-week next week and eventually dissipates. The bottom line is we are entering the time in hurricane season to be tropical weather aware, especially as storms enter the Caribbean.
Tropical Storm Emily made landfall on Anna Maria Island at 10:45 AM Monday morning with 45 mph winds. Strong rotation northeast of the center was spotted near the Sunshine Skyway Bridge during the time, which prompted a Tornado Warning for Manatee county, including Bradenton. As Emily moves further east away from the Gulf, it will weaken further Monday afternoon and evening.
Emily drenched the I-4 corridor southward early Monday. As of midday Valrico in eastern Hillsborough county saw over 8 inches of rain. St Pete had almost 6″ of rain and Bradenton had nearly 5″.The hardest hit areas were eastern Hillsborough, southern Pinellas, coastal Manatee and coastal Sarasota county. Wrap around moisture will fuel additional downpours through Monday evening as Emily moves east across the area. A Flood Watch is in effect until 8 PM for Hilllsborough, Pinellas, Manatee, Sarasota, Hardee, Desoto and Highlands county. Some rainfall totals may surpass 6″ through Monday evening.
The strongest winds were felt northeast and east of the center of circulation late Monday morning into midday. A wind gust of 57 mph was record at the fishing pier near the Sunshine Skyway Bridge. The Bradenton and Sarasota areas saw gusts near 50 mph, while further north in Tampa wind gusts were less than 20 mph. Wind gusts 30 mph+ are possible through Monday evening as Emily weakens over land and emerges back in the Atlantic early Tuesday.
The 11 AM advisory from the National Hurricane Center shows Emily weakening to a tropical depression Monday evening. It will re-strengthening to a tropical storm and accelerate northeast along a stalled frontal boundary over the warm Gulf Stream waters of the western Atlantic. Wrap around moisture and lingering tropical moisture will fuel scattered tropical downpours in Central Florida Tuesday and Wednesday.